1. Field of the Invention
The present invention relates to high-frequency generators and relates more particularly to a high-frequency generator that can be used especially with a plasma torch in which the treated gas is subjected to a high-frequency field.
2. Description of the Related Art
Patent FR 89 02 512 describes a high-frequency inductive plasma burner intended for the treatment of toxic or nontoxic effluents. This burner is subjected to a high-frequency field initiating the plasma on the very product to be treated.
It comprises a moveable part or a lateral injection allowing the flux of containment air to be adjusted, the torch being ignited by an electrostatic device, an adjustable orifice allowing the internal pressure in the torch to be modified, a spectral analyzer associated with a computer controlling the power of the generator, a suction at the outlet enabling the internal pressure to be reduced and an exchanger enabling the excess heat to be recovered.
High-frequency generators have been used for a long time for induction heating, for dielectric heating and for producing plasma flames from a gas and/or liquid jet and the like.
Such generators are usually designed to meet the requirements of a precise application but they are not suitable for all the abovementioned applications.
Their manufacturing cost is high because of the components used, such as the high-voltage capacitors, which may or may not have low losses, the power transmission lines and at least two power triodes.
The invention aims to remedy the aforementioned drawbacks of the known high-frequency generators by creating a high-frequency generator which can be used in many applications, especially those mentioned above, while at the same time having a low manufacturing cost compared with the known high-frequency generators.
The subject of the invention is therefore a method for the high-frequency treatment of a solid, liquid or gaseous product, consisting in making the product pass through an inductor supplied by a high-frequency generator, characterized in that the inductor has nontouching turns and in that said method consists in subjecting the product to an electrostatic treatment due to the effect of the capacitive impedance between the turns of the inductor and then in subjecting the product to an inductive treatment due to the effect of the inductive impedance of the said inductor.
The subject of the invention is also an inductor for the treatment of products, intended for implementing the method as defined above, comprising several turns which form a passage for a product to be treated, characterized in that the pitch of the turns and/or their diameter and/or the cross section of the wire forming the inductor depend on the frequency of the supply signal for the inductor.
The subject of the invention is also a high-frequency generator for the treatment of a solid, liquid or gaseous product by a high-frequency signal, characterized in that it comprises a single oscillating power lamp connected to a high-voltage supply line, an oscillating circuit with a distributed constant, the LC characteristics of which determine the desired oscillation frequency of the generator, said oscillating circuit being connected with the aid of the oscillating lamp via an isolating capacitor for blocking the DC component of the high-voltage supply, the high-voltage supply line being connected to the cathode of the lamp via an element for determining the voltage and the phase of the high-frequency signal and forming part of a complex feedback circuit connected between the oscillating circuit and the cathode of the oscillating lamp.
The subject of the invention is also an apparatus for the high-frequency treatment of a liquid, solid or gaseous product, comprising at least one treatment inductor surrounding a tubular pipe through which a stream of the product to be treated is intended to pass, said inductor being supplied by a high-frequency generator, characterized in that the inductor is an inductor as defined above and the high-frequency generator is a generator as defined above, the inductor being connected to the high-frequency generator via a frame coupled by mutual induction to the oscillating circuit, two matching lines connecting the frame to the inductor and a tuning capacitor forming, with the inductor, a circuit resonant at the frequency of the oscillating circuit.
Finally, the subject of the invention is the use of the method and of the equipment described above for:
reducing the amount and the average size of solid particles in a gas and/or
stripping solid particles off an organic gangue.